The internet is similar to a road network in that it has rules (protocols) that you need to follow and only a certain number of vehicles (data) can get through at a time (bandwidth). If too many vehicles try to go down the same road you get congestion (reduced bandwidth).
When two devices send messages to each other it is called handshaking - the client requests access, the server grants it, and the protocols are agreed. Once the handshaking process is complete, the data transfer can begin.
Protocols establish how two computers send and receive a message. Data packets travel between source and destination from one router to the next. The process of exchanging data packets is known as packet switching.
Protocols manage key points about a message:
TCP/IP (also known as the internet protocol suite) is the set of protocols used over the internet. It organises how data packets are communicated and makes sure packets have the following information: